"We gave pregnant mice with the NAD gene knocked out a regular dose of vitamin B3 and we found it prevented miscarriages and birth defects, over-riding the genetic block," Professor Dunwoodie said.

Scientists optimistic but cautious about discovery

Clinical geneticist David Amor, from the Royal Children's Hospital in Melbourne, said the key finding was the mechanism that a genetic deficiency of NAD could cause birth defects.

"What is most interesting is that these defects are potentially treatable if the mother is given niacin [vitamin B3] supplementation during pregnancy," he said.

And while vitamin B3 was shown to prevent birth defects in mice, he said whether it was the case in humans was yet to be determined.

Telethon Institute's Carol Bower called it an "exciting advance" but said it was not clear if a lack of vitamin B3 was the only cause of birth defects.

"It's not yet clear whether other malformations may be linked to this cause and whether dietary supplementation with niacin [vitamin B3] in humans would prevent this," Professor Bower said.

The Australian Medical Association (AMA) said it was an exciting development but may be premature to compare it to the discovery about folate.

"Most miscarriages are caused by chromosomal abnormalities which are not caused by a vitamin deficiency or a mineral deficiency, so it's not modifiable," said the AMA's president Michael Gannon.

An 'amazing future' for babies and their families

Memphis Jackson is just like any eight-year-old. He enjoys playing computer games and kicking a ball with his brother Cayliss.

But he's had to endure much more than most children.

He was born with hypoplastic left heart syndrome, where the left side of the heart can't adequately supply blood because the lower left chamber is too small and the left hand side valves don't work properly.

"Memphis has only got half a heart — so his half a heart is doing that work that our whole hearts do, so sooner or later it's going to burn out and stop working," he said.

Memphis's mother Tashan said being able to prevent heart defects like her son's would be amazing.

"Knowing that this breakthrough could mean that no babies are born with heart defects in the future, it just makes our hearts sing," she said.

"You can't put into words how amazing that is for the future of babies."

What does this mean for vitamin B3 and pregnant women?

Studies from the United States have shown up to a third of women have low levels of NAD in their blood and aren't getting enough B3 vitamin in their pregnancy supplements.

Scientists say women should take the recommended daily amount of B3 for pregnancy, which is 18 milligrams per day.

But Professor Dunwoodie said women who have problems absorbing nutrients, including those with diabetes, a high body-mass index or inflammatory bowel disease, may need a larger amount.

She said researchers would now start working on a test to measure a woman's NAD levels.

"The goal is to have a quick and easy test that could be done at the same time as a pregnancy test, either in urine or blood," she said.

The breakthrough was made possible by a grant from the National Health and Medical Research Council and philanthropic donations to the Victor Chang Institute, including the Chain Reaction Foundation, Key Foundation and the NSW Office of Health and Medical Research.